Error: Subscript 'subscript(_:)' requires the types 'String.Index' and 'Int' be equivalent

[mikage-961pro]

The following error message appears.

/Pods/WebLinking/Sources/WebLinking.swift:196:19: Subscript 'subscript(_:)' requires the types 'String.Index' and 'Int' be equivalent

Please revise them.
Thank you very much.

Development environment:
OS：macOS 10.15.2（19C57）
Tools:Xcode Version 11.3 (11C29)